Thread-cutting mechanism for sewing machines



Oct. 17, 1933. EB. ALLEN THREAD CUTTING MECHANISM FOR SEWING MACHINES Filed July 16, 1931 8 Sheets-Sheet l Nwv mi OC. 17, 1933. I E, B, ALLEN 1,930,637

THREAD CUTTING MECHANISM FOR SEWING MACHINES Oct. 17, 1933. E. B. ALLEN 1,930,637

THREAD CUTTING MECHANISM FOR SEWING' MACHINES Filed July 1e, 1931 a sheets-sheet s Oct. 17, 1933. E, B. ALLEN THREAD CUTTING MECHANISM Fon sEwING MACHINES Filed July 16, 1951 8 Sheets-Sheet 4 gwuentoz 8 Sheets-Sheet 5 E. E. IALLEN Filed July 16, 1931 mmf-:

THREAD CUTTING MECHANISM FOR SEWING MACHINES ""HHHHH Oct. 17, 1933. E. B. ALLEN THREAD CUTTING MECHANISM FOR SEWING MACHINES Filed Jul,r 16, 1951 8 Sheets-Sheet 6 MNM@ M mi

Oct. 17, 1933. E. B. ALLEN THREAD CUTTING MECHANISM FOR SEWING MACHINES Filed July 16, 1931 8 Sheets-Sheet 7 M. NN xm,

Oct. 17, 1933. E. B. ALLEN THREAD CUTTING MECHANISM FOR SEWING MACHINES Filed July 16, 1931 8 SheetS-Sheel'l 8 Patented Oct. 17, 1933 Unire STATES Parar erica THREAD-CUTTING MECHANISM FOR SEWING lv/IACHINES Application July 16, 1931. Serial No. 551,114.-

Claims.

This invention relates to sewing machines more particularly of the type adapted to sew a group of stitches and then come to rest. Machines of this type have commonly been provided with thread-cutting and thread-end holding devices of various kinds designed to out the needlethread at the end oi a sewing operation and hold the beginning end of the needle-thread under control during the formation of the initial stitches oi the next sewing operation. Devices which hold the beginning end of the needlethread above the work until the initial stitches are formed have been objected to because the beginning end of the needle-thread shows on the pper or right side oi the finished work. Devices which hold the beginning needle-thread-end below the work have been objected to, as heretofore constructed, because they have been arranged to clamp the thread-end against the under side of the needle-throat-plate and such thread-end is apt to be conspicuous in the finished work.

It is an object of the present invention to provide means for controlling the beginning end of the needle-thread in such a manner as to insure the shortest possible end of needle-thread on the under side of the finished work. Another object of the invention is to provide for the positive control of both the needle and under-thread of a two-thread sewing machine, so that every stitch from the beginning to the end of a sewing operation whl be perfectly formed, while avoiding conspicuous thread-ends in the finished work. A further object of the invention is t0 provide ertain safety devices to insure the proper cooperation of the working parts.

To the attainment of the ends in View the invention comprises the devices, combinations and arr ngeinents of parts hereinafter described and particularly pointed out in the appended claims.

The features of the invention and the advantages attained thereby Will be readily understood by those skilled in the art from the following detailed description oi a preferred embodiment i of the invention illustrated in the accompanying drawings, in which2- Fig. l is a right side elevation of a buttonhole s wing machine embodying the invention. Fig. 2 is a left side elevation of the machine.- Fig. 3 is horizontal section through the vertical member of the sewing machine gooseneck, showing the bei a-d work-clamp in plan. Fig. 4 Yis a rear end elevation of the machine. Fig. 5 is a vertical section on the line .Va-5, Figj2. Fig. 6 is a horizontal section on the line 6-6, Fig. 2.

(Cl. L12-252) Fig. 'Tris a perspective View of the barrel-cam shownin Figs. 5 and 6. Fig. 8 is a development of the barrel-cam shown in Figs. 5', 6 and 7. Fig. 9 is a bottom plan view of the machine. Fig. I0 is a section on the lineV lil-10, Fig. 3, showing the manually operated clamp-opening and thread-cutter tripping mechanism in locked condition, as when the machine is sewing; Fig. 4 showing these parts in unlocked condition, as when the machine is at rest.

Fig. 11 is a plan View of the clamp and thread- J cutter lock on. the line lil-l1, Fig. 4. Fig. Vl2 is a fragmentary left side elevation, similar to Fig. 2, with the parts of the stop-motion device in running position. Fig. 13 is a plan View of the lower work-clamp plates and the movably mountedl throat-plate oi the machine.

l-i is a side elevation, similar to Fig. 2, with the parts of the needle-thread cutter in open or thread-end-releasing position. Fig. l5 is a plan View of the throat-plate. Fig. 16 is a longitudinal' Vertical section. through the throat-plate. Fig. i7 is a perspective View of the throat-plate-shifting bar.` Fig. i8 is a vertical sectional view of the upper work-clamp-foot and throat-plate, with the needle throwing out a thread-loop after its initial descent in a sewing period. Fig. 19 is a similar view with the needle at the end of its first 11p-stroke, showing the beginning needlethread-end pinched against the under surface of the work by the movement of the throat-plate.

Fig. 20 is a bottom plan View of the manually operated bobhin-thread-cutting and -nipping mechanism, showing the bobbin-thread-cutter -nipper opened to thread-receiving position andy about to close.` Fig. 21 is a similar view at a slightly later stage,v showing the bobbin-threadcutter and, -nipper closed. Fig. 22 is a similar view at a still later stage, after recovery of the manually operated mechanism to its initial position, showing the. bobbin-thread-cutter actuatorbar latohed inineeotive pos.` tion to prevent the opening of the bobbin-thread-nipper and the release ofthe bobbin-thread-end by a repetition of the operation of the manually operated workciamp opening and bobbin-thread-cutting and nipper-ac'tuating mechanism. Fig. 23 is a perspective view of the bobbin-thread-cutter and -nipper-opening bar with a safety latch releasebar secured to it. Fig. 2li is a section on the line 2l-2i Fig. 22.

The invention is disclosed as embodied in a sewing machine oi the type adapted to sew straight as distinguished from eyelet-end buttonholes. The machine frame is formed with a bed 1 from which rises the vertical member 2 of the overhanging gooseneck 3 terminating in the head 4 in which is mounted the usual reciproeating and laterally vibrating needle-bar 5 carrying the needle 6.

The machine is driven by a main-shaft 7 carrying the usual tight and loose belt-pulleys, 8 and 9, respectively, and controlled by a stop-motion device, preferably constructed substantially in accordance with the isclosure of the Allen Patent No. 743,213, of Nov. 3, 1903, and the Allen and Myers application, Serial No. 272,416, led Apr. 24, 1928. Such a stop-motion devic-e comprises a tilting stop-motion lever 10 fulcrumed on the trunnion screws 11 and carrying an upwardly spring-pressed plunger 12, Fig. 4, cooperating with a notched stop-cam 13 geared to the mainshaft 7. The stop-motion lever 10 has a laterally extending arm 14, which carries a belt-shipper 15 arranged to guide the belt 16, Fig. 1, onto the tight pulley 3 when the stop-motion lever 10 is tilted to its inclined position, Fig. 12, to carry the upper end of the stop-plunger 12 laterally out of engagement with the notched stop-cam 13. The stop-motion lever 10 also has a forwardly extending arm 17 to which is connected a vertical pull-rod 18 extending downwardly through an aperture 19 in the bed 1 and having connected to its lower end a chain 20 connected to the usual starting pedal (not shown).

When the starting rod 18 is pulled down by the operator to start the machine, it is retained in its down position by the spring-pressed latchlever 21 iulcrumed at22 below the bed 1, which latch-lever` enters a notch 23 in the side of the rod 18. At the end of a sewing period the usual tripping point 24, Fig. 9, on the feed-wheel 25, engages the point 26 on thelatch-lever 21 and shifts such lever out of the notch23, thereby releasing the starting rod 18 which is projected upwardly by the recovery spring 27, from the position shown in Fig. 12 to the positionl shown in Fig. 2, to stop the machine.

Cooperating with the needle 6, below the bed 1, is the usual oscillatory shuttle 28 carrying the thread-case 29, Fig. 1.8, for the bobbin-thread 3i).

The work-clamp comprises the usual longitudinal slide-plate 31 on which is pivotally mounted at 32 the upper clamp-lever 33 carrying at its forward end the Vusual rectangularly apertured clamping foot 34 which clamps the work upon the plate 31 at the opposite sides of the central longitudnal slot 35` therein. The longitudinal slide-plate 31 is slidably mounted in ways in the cross-slide plate 36 which, in turn, is mounted in ways in the bed 1. The slide-plates 31 and 36 `of the work-clamp are moved in the usual manner to place the stitches around the buttonhole by the usual feedng connections with the feedwheel 'which has in its upper face the longitudinal feed-cam-groove 37 and lateral feedcam-greove 38. The work-clamp and its :feeding means, as above described, is old in the art and is disclosed, for example, in the U. S. patent to Allen, No. 738,591, of Sep. 8, 1903, which has been developed to the modern forni shown in the U. S. patent to Wood, No. 1,613,634, of Jan. 11, 1927.

Supported the cross-slide plate 36 within the slot of the longitudinal slide-plate v31 is the throat-plate 39 formed with the usualnecdieaperture 40 and clearance slot 4l for the buttonhole cutting knife 42. Heretofore, as shown in the Wood Pate t No. 1,613,634, theV throat-plate has been screwed fast to the cross-slide plate. According to the present improvement I provide an element which is movable relative to and in contact with the under side of the work, after the iirst needle-loop has been seized by the under thread mechanism, such element wiping across the path of the needle below the work to engage the beginning needle-thread-end and pinch it against the under surface of the work to hold such end under control during the formation of the initial stitches. As a preferred means to this end thc-throat-plate 39 has been provided with two separate and distinct needle apertures, the regular sewing aperture 46 and a rst-sttch aperture 43. The cross-bar or bridge 44 between such apertures constitutes the thread-end holding means. This bridge may, in part, be constituted by a plate spring insert 45 having a needle-aperture in register with and constituting a part of the first-stitch aperture 43 in the throat-plate.

The throat-plate 39 is supported upon but may move relative to the cross-slide plate 36 in the guideways 45 provided in the longitudinal slideplate 3l, Fig. 24. When the machine is started, the throat-plate is in position for the needle to down-stroke through the first-stitch The throat-plate is then shifted, as will be hereinafter explained, to register the regular sewing aperture 40 with the needle-path for the remainder of the sewing operation.

The throat-plate 39, Figs. 13-17 inclusive, carries two spaced depending pins 46 between which extends the transverse arm 47 rigid with the longitudinal slide-bar 48 mounted in the bed 1 and for led at its rearward end with a slot 49 ent by the vertical 56 iulcrumed at 5l on tile bracket 52 screwed to the under side of bed 1.

The arm is shifted from the position shown in to that shown in Fig. 14 to shift the threat-plate from the position shown in Fig. 18 to that shown in Fig, 19 by means of the linkconnection 53 with the lower endof the lever 54 fulerunied at 55 within the vertical hollow frame-member 2. The lever 54 is formed at its upper with a boss 56, Fig. 5, in which is mounted the spring-pressed slide-bolt 57 adapted to enter the cam-groove 53 in the barrel-cam 59 on the main-shaft 7. The slide-bolt 57 isvheld out oi the cai groove 58 by engagement of one arm 69 of the .l-crank latch-lever 60, 61 under .ne collar 62 .ii-xsd to the slide-bolt 57. The bellcrank latch-lever 60, 61 is fulc'ruined on the studscrew 63 carried by the lever 54.

When the machine is at rest, the arin 61 of the bell-crank latch-lever 69, 61 is engaged by the catch 64, Fig. 2, fulcrurned at 65 on the starting rod 18. A down-pull on the rod 18 to start the machine causes the catch to withdraw the arm 60 of the bell-crank latch-lever from the collar 62, thereby releasing the slide-bolt 57 which is projected by its spring into the dwell-portion 58 of the cam-groove 58 at the point 57', Fig. 8. In the down-motion of the stal g rod 18, the catch 64 first swings the bell-crank latch-lever 60, 61, to release the slide-bolt 57 for cooperation with the cam-groove 53 and then wipes past the arm 61 releases the bell-crank latch-lever 60, 61 which is pulled by its spring 6l', Fig. l2, into engagement with 'the side of the collar 62V and is ready to engage under the collar 62 when the slide-bolt57 is nally ejected from the cam-groove 53 and hold the slide-bolt 57 in e'ected position. Compare Figs. 2 and 12.

When the'slide-bolt is irst projected into the caro-groove 58 it dwells for a certain period while the needle makes its ilrst down-stroke and throws tion and the final stoppage of the main-shaft, by the up-motion of the stop-plunger 12 into the notch of the stop-cam 13. To this end there is fulcrumed on the bracket 93 at 110, a latch-lever 111 which in its dotted line position, Fig. 11, enters a lock-notch 112 in the rod 92 depending from the clamp-opening lever 99. rIhev lever 111 has a hooked extension 113 which embraces the locking bar 114 pivotally connected at its upper end to the lever 96 and formed at its lower end with a locking shoulder 115 adapted to hook under the edge 116 of the bracket-plate 93, as shown in Fig. 16. The latch-lever 111 is formed at its forward end with an upstanding ear 117 adapted to be engaged by the lower end of a lever arm 118 fixed to the stop-motion controlledrockshaft 81.

When the stop-motion lever 10 is tilted to running position, Fig. 12, the arm 84 is carried inwardly beyond the'end of the plunger 83 and the spring 82', 4, pulls the arm 82 downwardly and rocks the shaft 81, thereby moving the arm 118 outwardly from full line to dotted `line position, Fig. 11, and permitting the latchlever 111 to be shifted by its spring 111 to dotted position in which it engages the lock-notch 112 in the rod 92 and holds the lock-shoulder 115 of the bar 114 .under the edge 116 of the plate 93. Thus the levers 90 and 96 and hence the workclamp and needle-thread cutter release mechanisms are both safely locked until the machine comes to rest with the needle at its highest point.

The bobbin-thread-cutting and -nipping mechanism is constructed substantially in accordance with the disclosure of the Allen application, Serial No. 400,763, led Oct. 19, 1929, with the addition of a safety latch to prevent the opening of the bobbin-thread-cutter and -nipper blades by a` repetition of the operation of the clamp-opening mechanism. The mechanism comprises spaced stationary cutter and nipper blades, 119, 120, respectively, between which are pivoted at 121 the movable cutter and nippel blades, 122, 123, respectively. The cutter-blade 119 has extending laterally therefrom an actuating arm 124 formed with a downturned lio 125 affording a striking face for engagement by the cutter-operating push-bars 126, 127.

As the bobbin-thread-cutter and -nipper is positioned and has a range of action slightly at one side oi the needle path, it will not of itself catch the under thread. Means are therefore provided to carry the Linder thread into the rangek of action of the device. For this purpose there is pivoted at 123 on the cross-'slide plate 36 a bobbin-thread-engaging arm 129 the free end of which is formed with a thread-catching hook 136 which carries the bobbin-thread laterally between the open jaws of the thread-cutting and -nipping device. The arm 129 is actuated by a link-connection 131 with the slide-bar v89 which is connected to the clamp-opening mechanism.

Slidably mounted on the under side of the cross-slide plate 36 between the guide-pins 132, 133, is the push-bar 126 previously referred to, which carries a screw 134 passing through a slot in the thread-catching arm 129. The tail 135 of the push-bar 126 is inclined to the leit, Fig. 29, and is connected by a spring 136 to an arm 137 rigid with the cross-slide plate 36. The nose 133 of the push-bar 126 is` inclined to the right and is adapted to engage the lip 125 of the threadcutter arm 124 and open the thread-cutter to the position shown in Fig. 20, (which is near its fully open position), during the thread-bending movement of the thread-catching arm 129. During the slight further and nal movement of the arm 129, the inclined tail 135 of the push-bar 126 engages the guide-pin 132, Fig. 20, and is deilected to the right, thus swinging the push-bar 126 about the guide-pin 133 as a iulcrum and disengaging its nose 138 from the lip 125, whereupon the spring 124 quickly swings the thread-cutter and -nipper blades 122, 123, to closed position, Fig. 21.

Pivoted on the screw-connection 139, between the link 131 and the slide-bar 89, is a springpressed latch 140 the free end-wall 141 of which is engaged by the pin 142 on the push-bar 126, Fig. 22, after an initial actuation of the push-bar 126 and holds such push-bar away from the lip 125 so that it cannot re-engage such lip and open the thread-nippelA after such nipper has caught the bobbin-thread-end, even though the workclamp be repeatedly opened and closed in the introduction of work to the work-clamp. Y

At the beginning of the next sewing operation and after the initial stitches have been formed, the vnipped bobbin-thread end is released by movement of the push-bar 127 from full line to dotted line position, 22, during which movement the end of the push-bar 127 engages the lip 125 and opens the thread-cutter and -nipper blades. There is a second push-bar 143, Fig. 23, secured to the push-bar 127. The push-bar 143 engages the latch 140 and shifts its end-wall 141 out of engagement with the pin 142 after the initial stitches have been formed, thus restoring the push-bar 126 to operative relation with the lip 125 of the thread-cutter and -nipper blades. The push-bars 127 and 143 are formed at the inner end of the slide-bar 144 from which depends a stud-pin 145 entering a slot 146 in one end of a lever 147 fulcrumed at 148 below the bed 1 and carrying anadjustable cam-follower nose 149 which is engaged by the bobbin-thread nipperopening cam 150 on the feed-wheel 25 which, of course, is driven in the usual manner and makes one-complete revolution per buttonhole-producing cycle.

The throat-plate-shifting slide-bar 48 is provided vwith anextension 151 which is formed with a shoulder 152 engaged by the spring-pressed catch Y153, Fig; 22, when the throat-plate 39 is shifted to regular sewing position after the first descent of the needle. throat-plate in sewing position. At the end of a sewing operation, the manual operation of the clamp-opening mechanism causes the arm 154 which is rigid with the bobbin-thread-bender arm 129 to swing from the position shown in Fig. 22 to that shown in Fig. 21, during which movement the screw-pin 155 on the arm 154 engages the cani-shaped tail 156 of the latch 153 and swings such latch to release it from the shoulder 152, following which the end of the arm 154 engages the end Vof the slide-bar extension 151 and shifts the arm 111, as shown in Fig. 4 and in full lines in Fig. 11. The needle-thread end is held by the needle-thread-end nipper 67 above the work. The bobbin-thread end is-held by the nipper-blades 126, 123, as shown in Fig. 13. The movable throat-plate is in its rearward position with its This catch 153 locks the "frst'l-stitch iaperture 43 in --This motion causesthe catch 64 to engageV and register with the needle.4

v After placing work in the work-clamp, the operator pullsldown on the startingrod 18 to tilt the stop-motion lever to running position, Fig.V 12.

v swingthe bell-crank latch-lever S0, 61 to release the plunger 457 whichenters the cam-groove 458 c .inthe barrel-cam 59 on the main-shaft and re- Vceives one back and forth movement. The nrst part..58.. of the cam-groove-is a dwell producing portion which gives thefneedle time to make-its v.iirst descent and present its loop tothe shuttle 28.

A'ssoonas the needle rises-out otljiework, the .inclined part 58" oi the cani 453 starts-to move .theplunger 5.7 and its carrier Vlever 54 to open the upper threadnipperand release the needlethread-end, at the same time shifting the throatplate 39.from `i'rst-s'titch position to regular ksew- 4,ingposition The shuttle 28, in its continuedA movementv .pulls.V down the released needle- -`.thread.-end.and the 'usual take-up (notshown) lio draws this end to a iinal position between the .spring plate insert 45 and the under surface of the work, Fig. 19. The latch 153 locks the throatplate shifting bar 48, 151 in its forward-position.

1 After three or' 'four stitches have been sewn, c the cam'150 on the feed-wheel 25 ac'tuates the "slide-bar 144 to release the bobbin-thread from the bobbin-thread-nipper and reset the bobbinthread-cutter and -nipper operating push-bar 126."' 'i At the end of the sewing operation, the iinal rise ofthe stop-motion plunger i2 into thenotch l 'of the stop-cam 13, rocks the shaft 3l which vfunc- 'tions'onlyto release the' needle-thread tension v(not shown) and to shift the 'clamp-lock 111 'to ulldine position, `Fig.v 11, toV unlock the work- .clamp and needle-thread-cutter release mechanism.

Y'The op'eratornowexertsV a down pullonthe lever 96. 'The first motion rocksthe lever 96'upon "and relative to lthe lever 90 to release the needlethread-cutter and `nipper by'tripping the latch 74. A further movement'shifts the latch 153 to release the needle-throat shifting bar 151.V A still further movement causes the arm.l54 to engage -and;return' the bar 151' to its rearward position and atthe Sametime the under-thread-cutting .and ,-nipping mechanism is actuated. In the "operation ofthe under-thread-cutting and -nipping mechanism, the pull exerted on the bobbinthread by thethread-catching hook 130, draws down the severed end of needle-thread, vjust' be- 0 'fore the bobbin-threa'd 'is severed; The inclined "tail 135 of the'bobbin-thread-outter actuator-bar 126 causes such bar to swing suihciently to permit the end wall A141A of the safetylatch 140 to drop into position, Fig. 21, to prevent reopening of the' under-thread-nipper by repeated operations o the` clamp-lifter.v During thedown-motion of the clamp-lifter lever 90, the roller-stud '94 depresses the tail33 of thework-clamp lever 33 and raises the clamp-foot 34 to release the work..

Having thus set forth the nature of the invention, whatl claim herein isz- Y l' L.1. .The combination. with a-reciprocating needle and work-feeding` means, of means below the workcfor-drawingdown the beginning end of the needle-thread, `means fory pinching said end against the under surface of the work.

2. Thefcombination'with a reciprocating needle, work-feeding means, anda needle-threadcutter and -nipper above the work, of means reciprocation of the needlmeans fordrawing down the released beginning needle-thread-end,

and means for pinching said end vagainst the under surface of the work.'v

3. The combination with a reciprocating needle and work-feeding means, of thread-end holding meansin engagement with the under surface of the work and movable across the path 'of the initial descent of the needle after the needle has risen. e,

4. In a sewing machine, the combination with stitch-forming mechanism including a reciproeating needle and complemented loop-taking means, of means operating before the second descent of' the needle tohold the beginning end of the needle-thread against the under surface. of the work. j

5. In a `sewing machine, vthe combination with stitch-forming mechanism including a reciproeating needle, complemental loop-taking. means, and a throat-plate, of means for moving said throat-plate relative to the work after Vthe initial descent of the needle, tov hold the beginsurface of the Yworin-following the initial descent Vof the needle and the drawing 'down of the beginning end ofthe needle-thread, to hold such thread-end against the under surface of `the work during the formation of a succeeding stitch. 7. 1n a sewing machine, a reciprocating'ne'edle, a work-holder, a stop-motion mechanism, a needle-thread cutting and -nipping device disposed above the work, means for closing said device at the, end of a sewing period, means for opening said device during the initial reciprocation of the needle 'inf the next-'sewing period, means below the'workior-"drawing down the beginningneedle-thread-end `after, it isreleased by said' device,

and-means operative beforethe second descent of the needle l'to hold such end against the under surface rof-"the work: 1

stitch-'forming mechanismincluding a reciprocatingneedle,a work-holder, means for relative- -lymoving the 'stitch-forming mechanismV and work-holder to sew a group of stitches,y a 'stopmoticn-device for arresting 'the'rnachine at the end of'aV sewingsperiod, and means operating be- Yfore -the'second-des'centof theneedie Ato hold the beginning end-of theneedle-thread against the underside ofthe-work.-

9. -In'a sewing machine', the combinationV with stitch-forming mechanism including `a reciprocatingneedle; ofwa throat-plate havingia plurality'of needleapertures, and" meansifor' moving said throat-platerelative" to the work afterth'e initial descent'ofthe needle tnroughoneof said apertures to "register another of said apertures with the needle-path;

10;'.The'combination'with a reciprocating needle, of a throat-plate having a plurality of openings for passage of said needle, and -means for relatively movingsaid throat-plate "and the work inffa-direction parallel to a line connecting said I., 1. L.. .i KA"11. vIn asewing machine, aneedle-throat member -having a plurality o'fneedleopening's and -a spring insert between said openings for yield- 8; In asewing `machine', thecon'ibination vwith ingly holding the beginning needle-thread-end against the under surface of the work.

12. A sewing machine having a reciprocating needle, and a throat-plate having an element movable across the path of the needle and relative to the work after the initial descent of the needle, to pinch the needle-thread against the under surface of the work.

13. In a sewing machine, the combination with a reciprocating needle, of a throat-plate having a plurality of entirely separate and distinct openings for receiving said needle.

14. In a sewing machine, the combination with a reciprocating needle, a loop-taker, a stop-motion device, and a needle-thread-cutter and -nipper, or" a cam and follower device and connections movable during the initial reciprocation of the needle to first open said cutter and nipper and subsequently hold the beginning end of the needle-thread against the under surface of the work.

15. In a buttonhole sewing machine, stitchforming mechanism including a reciprocating needle, a work-clamp, means for relatively moving the stitch-forming mechanism and workclamp to sew around a butuonhole, a needlethroat-member having a plurality of needle- 1 clearance apertures one of which is in register with the needle-path when the machine is started, means operated by a moving part of the machine for shifting said needle-throat-mernber after the initial descent ofthe needle to register the other needle-clearance aperture with the needle-path, manually operated bobbinthread-cutting and -nipping mechanism, and means operated by said mechanism for restoring the needle-throat member to initial position.

16. In a buttonhole sewing machine, a bed, a cross-slide plate mounted on said bed, a longitudinal slide-plate mounted on said cross-slide plate and formed with a slot, and a needle-throat plate mounted in said slot and movable relative to said cross and longitudinal slide-plates.

17. In a sewing machine, a reciprocating needle, a loop-taker, a bobbin, a work-holder, a stop-motion device, manually operated means for opening the work-holder to release the work, a bobbin-thread-cutter and -nipper, an actuator for said cutter and nipper connected to be operated by said manually operated work-holder opening means, and means for preventing reengagement of said cutter and nipper by said actuator after an initial actuation of said cutter and nipper.

18. In a sewing machine, a reciprocating l needle, a loop-taker, a bobbin, a work-holder, a

stop-motion device, manually operated means for opening the work-holder to release the work, a bobbin-thread-cutter and nipper, an actuator for said cutter and nipper connected to be operl ated by said manually operated work-holder opening means, a latch for preventing re-engagement of said cutter and nipper by said actuator after an initial actuation of said cutter and nipper, and means actuated by a moving part of the -1 machine for tripping said latch Vin the ensuing sewing operation to re-establish operative relation of said actuator to said cutter and nipper.

19. In a sewing machine, a frame includingy a bed and a gooseneck rising therefrom, stitchforming mechanism including a needle, a workclamp, means for relatively moving the stitchforming mechanism and work-clamp to sew a group of stitches, a main-shaft journaled in said gooseneck, astop-motion device for controlling the period of operation of said main-shaft, a needle-thread cutter, a stop-motion-controlled rock-shaft mounted upon and exteriorly of said gooseneck in parallelism with said main-shaft, a clamp-opening lever fulcrumed at one end upon and movable relative to said rock-shaft, a manually-operated lever fulcrumed on the free end of the clamp-opening lever and having an inwardly and downwardly extending arm for operating the needle-thread cutter, and a lost-motion connection between said levers, whereby the needlethread cutter will be operated before the clampopening lever is moved.

20. In a sewing machine, a frame including a bed and a gooseneck rising therefrom, stitchorming mechanism including a needle, a workclamp, means for relatively moving the stitchforming mechanism and work-clamp to sew a group of stitches, a main-shaft journaled in said gooseneck, a stop-motion device for controlling the period of operation or" said main-shaft, a

needle-thread cutter, a stop-motion-controlled rock-shaft mounted upon and exteriorly of said gooseneck in parallelism with said main-shaft, a clamp-opening lever fulcrumed at one end upon and movable relative to said rock-shaft, a manually-operated lever fulcrumed on the free end of the clamp-opening lever and having an inwardly and downwardly extending arm for operating the needle-thread cutter, a lost-motion connection between said levers, whereby the needlethread cutter will be operated before the clampopening lever is moved, means for locking said manually-operated lever and said clamp-opening lever while the machine is sewing, and means connected to said rock-shaft for unlocking said levers when the machine comes to rest,

21. In a buttonhole sewing machine, a bed, a cros's-slide-plate mounted on said bed, a longitudinally slotted longitudinal slide-plate mounted on said cross-slide-plate, a reciprocatory needle, a throat-plate carried by said cross-slide-plate within the slot in said longitudinal slide-plate, a clamp-foot, and means for shifting said throatplate relative to said cross-slide-plate.

22. In a sewing machine, the combination with a reciprocatory and laterally vibratory needle, and a loop-taker, of a throat-plate for supporting the work against the penetrative thrusts of the needle, and means for moving said throat-plate transversely of the plane of vibration of said needle. o

23. In a buttonhole sewing machine, a throatplate having a needle-receiving aperture and a knife-receiving slot, and means for moving said throat-plate in a direction lengthwise of said knife-receiving slot.

24. In a sewing machine, in combination, a reciprocatory needle, a loop-taker, a throat-plate intermediate said needle and loop-taker, a stopmotiondevice and automatic means for moving said throat-plate after the rst penetrative thrust of the needle in the formation of the initial stitches, said means remaining stationary during the remainder of the sewing period.

25. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory needle, a throat-plate, and an upper workclamp foot, of means for drawing down the beginning end of the needle-thread and means vfor nipping the drawn down end of the needlethread between the throat-plate and work-clamp foot.

EDWARD B. ALLEN. 

